Linear segmented polyurethane elastomers

ABSTRACT

THIS INVENTION RELATES TO HIGHLY ELASTIC LINEAR SEGMENTED POLYURETHANES COMPRISING SEGMENTS OBTAINED FROM CERTAIN SEMI-CARBAZIDE HYDRAZIDES CHAIN EXTENDING AGENTS, HIGHLY ELASTIC FIBRES THEREOF AND TO A PROCESS FOR THE PREPARATION OF SAID LINEAR, SEGMENTED POLYURETHANE ELASTOMERS.

Un t d Sa r o 'ABSTRACT OF THE DISCLOSURE This invention relates to highly elastic linear segmented polyurethanes comprising segments obtained from certain semi-carbazide hydrazides chain extending agents, highly elastic fibres thereof and to a process for the preparation of said linear, segmented polyurethane elastomers.

It is already known that substantially linear, relatively high molecular weight NCO-terminated preadducts (hereinafter referred to in short as NCO-pr'eadducts or NCO- prepolymers), prepared from relatively high molecular weight polyhydroxy compounds (optionally in the presence of relatively small quantities of low molecular weight diols) and excess molar quantities of organic diisocyanates, can be reacted in highly polar organic solvents such as dimethyl formamide with substantially bifunctional chain extenders containing two active hydrogen atoms, resulting in the formation of viscous solutions of substantially linear polyurethane elastomers which can be processed from the solution and converted into elastic filaments or films. Suitable chain extenders include in particular diamines, preferably aliphatic or araliphatic diamines, hydrazine or dihydrazide compounds. Diamines and hydrazine are highly reactive with respect to the NCO- preadducts which preferably comprise aromatically linked NCO groups, with the result that non-uniform crosslinked components (jellyfish) are likely to be formed in the elastomer solution. In order to reduce this crosslinking tendency, a number of chemical modifications involving the use of expensive technical equipment are necessary.

In contrast, the reactivity of dihydrazide compounds as chain extenders (cf. German Patent No. 1,123,467). with NCO pre-adducts is reduced to such an extent that their reaction can be displaced particularly favourably without the disadvantage of chemical cross-linking and the accompanying formation of so-called jellyfish in the solution. Polyurethane elastomer solutions of this kind can be spun into highly elastic filaments of outstanding 3,640,937 Patented Feb. v8, 1972 ture, in hot water or steam in particular, is not satisfactory. Thus, elastomer filaments of this kind can be stretched under minimal initial strain to a much greater extent in hot air than in air at room temperature, and after relaxation show considerable residual elongation. In particular, when elastomer filaments in a stretched state (for example at 100% elongation) are hydrothermally treated (for example in boiling water), the residual elongation levels are still high. These relatively low resistance in elastomer filaments, such as these extended with certain hydrazides, to extension under thermal or hydrothermal conditions is particularly undesirable in finishing and dyeing processes.

In addition, elastomer filaments of this kind are sensitive to the presence of traces of heavy metal ions. This occurs for example when carbodihydrazide is used as chain extender in the reaction with NCO-preadducts. Boiling with water containing copper ions in small quantities, for example, is sufficient to produce a change in the colour of the filaments to pinkish-red, spoiling the appearance of undyed fabrics, even if there is no evidence of the strength property being affected. Oxalic acid dihydrazide is almost insoluble in dimethyl formamide and, after re action with NCO-preadducts, gives elastomer filaments which, like filaments containing units from malonic acid or succinic acid dihydrazide chain extenders, are extremely sensitive to hydrolysis and are not sufficiently resistant to strain under hydrothermal conditions.

If ethylene bis-semicarbazide or hexamethylene bis semicarbazide, for example is used instead of the dihydrazide compounds as chain extender in the reaction with the NCO-preadducts, the elastomer solutions obtained cannot be spun because they become gel-like in consistency after a short time, or even during their preparation. The polyurethane elastomers formed are probably inadequately solvated by the solvent with the result that they are precipitated in the form of a pasty gel which is either impossible or extremely diificult to convert into filaments or films.

An object of this invention are highly elastic substantially linear segmented polyurethanes obtained from essentially linear relatively high molecular weight NCO- preadducts and chain-extending agents, which contain the chain-extender segment I --NHNHCO-N I-I- (CH C ONH NH- (x=l or 2) and which are obtained by reacting the relatively high molecular weight NCO-preadducts with'su'b}: stantially equivalent quantities of aliphatic s'emicarbazide' hydrazides of the formula 5 H N NHCO-NH (CI-I CO+NH NH (x l' or 2), in highly polar'organic solvents, and 'subse-" quently removing the solvents by evaporation or coagulation. In a preferred embodiment this reaction; is'carried outin such a way that segmented polyurethane elastomers are obtained consisting of reaction products of the essen'-- tially linear relatively high molecular weight .NCO-pre: adducts with chain extenders containing at least based 'on all the chain-extender segments present, of a chain extension segment of the structure (x=1 or 2).

A further object of the invention is an essentially linear segmented polyurethane elastomer consisting of a reaction product of an essentially linear relatively high molecular weight NCO-preadduct and a chain extending agent selected from the group consisting of and a conventional chain extending agent selected from the group consisting of water, hydrazine, a glycol, an amino alcohol, a diamine, and a dihydrazide.

In view of the known properties of elastomers containing units obtained from dihydrazide as chain extenders, and the behaviour of corresponding bis-semicarbazides as chain extenders, we found it extremely surprising that the aliphatic semi-carbazide hydrazides of the formula (x=l or 2), gave elastomers with outstanding properties far superior to those of comparable dihydrazide-extended elastomers.

Polyurethane elastomers extended with B-semicarbazide propionic acid hydrazide (x=2 in the above formula) have particularly outstanding properties, with the results that this hydrazide is preferably used as the bifnnctional compound containing two active hydrogen atoms for chain extending the NCO-preadducts, particularly in cases where the polyurethanes are to be converted in elastomeric filaments. After the solution has been wetor dry-spun in the usual way, elastomers such as these give high-grade elastomeric filaments with substantially improved thermal and hydrothermal properties, coupled with outstanding strength and elastic properties. The filaments and films are colour stable in the presence of heavy metals, for example copper ions, and are much more resistant to hydrolysis than comparable dihydrazide compounds. In addition, the polyurethane elastomers are readily soluble in the usual solvents, such as dimethyl formamide or dimethyl acetamide.

The favourable set of properties is illustrated by the comparison tests in the examples which follow.

The compound preferably used as chain extender, namely B-semicarbazide propionic acid hydrazide, is a new compound. Even minor changes in structure, for example with progression in the homologous series to "ysemicarbazide butyric acid hydrazide (x=3 in the above formula), are sufiicient to reduce the properties of the elastomers chain-extended in this way in connection with their behaviour under thermal and hydrothermal CQIldiv tions, to below the adequate limit, for example, for elastomeric filaments. The outstanding properties of the products' is only obtained with aliphatic semicarbazide hydrazide. as defined above (which formula x=1 or 2 (prefer- 'b y r A further object of the invention are the following processesfor ,preparingpolyurethane elastomers containh ri v w -NHCQ'NH+(C Q)X,- I

(x l or 2 (a) Reacting the NCO-preadducts of relatively high molecular weight dihy'dr'oxy compounds 'and'excess' molar quantities of diisocyanates (NCO-content of the preadduct approximately between 1% and 6 NCO, based on the solids content) with substantially equivalent quantities of bifunctional low molecular weight chain extenders containing two active hydrogen atoms in the presence of highly polar organic solvents, aliphatic semicarbazide hydrazides of the formula (x=1 or 2) being used, as chain extenders.

(b) As (a) except that in addition to at least 55 mol percent of the semicarbazide hydrazides claimed up to mol percent of conventional bifunctional compounds with at least two active hydrogen atoms and molecular weights of from 18 to about v300 (for example water, hydrazine, diamines, dihydrazides) are used as chain extenders.

(c) Reacting an 'NCO-preadduct prepared from relatively high molecular weight dihydroxy compounds and low molecular weight diols with molecular weights of from 62 to about 300 and preferably containing 1 or 2 tertiary amino groups in the molecule, in quantities of from about 0.01 to .1.0 mol per mol of relatively high molecular weight dihydroxy compound, and excess molar quantities of diisocyanates (NCO content ofsolid NCO- preadduct approximately between 1% and 6% NCO) with substantially equivalent quantities of aliphatic semicarbazide hydrazides- (x=l or 2) as chain extenders in highly polar solvents.

(d) Reacting an NCO-preadduct prepared as described in (c), with substantiallyequivalent quantities of chain extenders, comprising at least mol percent of the semicarbazide hydrazides H NN-HCONH-( CH -CONH--NH (x=1 or '2) and up to 45 mol percent of conventional chain extenders being used.

The products obtained by the process are linear, seg

mented polyurethane elastomers consisting of intralinear, segments of the structure I in which D represents a long chain, divalent substantially aliphatic polymer radical without any substituents reactive to isocyanate, and having a molecular .weight of from 600 to 5000 and a melting point below '60" C.; R reprsents a divalent organic radical of an aromatic, aliphatic, cycloaliphatic or araliphatic diisocyanate;G repre-' sents a divalent aliphatic cycloaliphatic or aralip'hatic radical of a dialcohol with molecular weight of from 62 to 300, preferably containing one or more tertiary aliphatic amino groups, without the :terminal hydroxyl groups; r is an integer of at least 1, e.g. from 1 to 5,

than 300% and an inherent viscosity (as measured in a solution in hexarnethylphosphoramide.at 25 C.) of at least 0.5 in order to obtain adequate elastic properties in the'filaments and films.

In addition to the structural segments of Formula I, a

maximum of up .to 45% byweight of the substantially clude-polyesters', polyesteramides, polyethers,'polyacetals, linear segmented polyurethane elastomers may preferably polycarbonates or poly:-N-alkylurethanes,- other groups consist of intralinear segments'tof structure II which are suchas ester,- ether, amide, urethane, N-alkylurethane obtained by reacting the NCO-preadducts with convengroups optionally being present in'the above-compounds, tional chain extenders such as water or compounds conwith molecular weights of from 600 to'5000. and preferataining two terminal NH groups and. which have the bly from 800 ton3000, and having melting points preferastructure II blybelow 60 C., in particular, below'45C. It is also in which D, G, R, r, s, m and n are as defined above, possible to use mixtures of the relatively high molecular 7:0 or 1 and Z represents the radical of a conventional Weight polyhydroxyl compounds.

chain extender with two terminal NH groups, Particularly useful are polyesters of adipic acid and H dialcohols, if desired, mixtures of dialcohols, for ex- H2N Z N 2 ample ethylene glycol, propylene glycol, 1,4-butane diol,

from which these NH -groups have been removed. Z 2,5-hexane diol, 2,2-dimethyl-l,3-propane diol, 1,6-

can be absent or a divalent organic radical with from 2 hexane diol, 2-methyl-1,6-hexane diol, 2,2-dimethyl-1,3-

to 13 carbon atoms, free of any substituents which react hexane diol, p-bis-hydroxylrnethyl cyclohexane, 3-methy1- with isocyanates, for example a divalent aliphatic or cyclo- 1,4- e tane diol, 2,2-diethyl-l,3-propane diol, more aliphatic Tadical With at most 13 Carbon atoms, Preferably preferably mixtures of these with diols or mixtures of h diols containing 5 or more carbon atoms, because poly- CH2CH esters of this kind show a very high resistance to hydrol- I ysis. When the diols contain branched alkyl radicals, the

R polyesters also show outstanding low temperature elastic- R=H,CH ity in the end products. Polyesters, of narrow molecular weight distribution (obtained by polymerising capro- 2)s 2 8 lactones with glycols) are also eminently suitable start- L, H ing materials.

Polyurethane elastomers that are highly resistant to hydrolysis can be obtained from polyalkylene ethers such as polytrimethylene ether diols, polypropylene glycols,

and preferably from polytetramethylene ether diols which may also be used as mixed polyethers (by co-condensing small quantities of epoxides such as propylene oxide or '=H,c1-I epichlorhydrin), or after terminal group modification, for y 1 40 example replacing the OH groups by the OCO-N(alkyl) CH CH OH CH2 OH2 group. Polyepichlorhydrins with terminal OH-groups in cis/ trans mixture the aforementioned molecular weight range are also suit- CH /OH mdial able for use in production of fireproof end products. Basic CHFCHg polyethers whose tetriary amino groups may be a divalent aromatioradical without any condensed i quaternised at least in part, are also suitable. lolycarpreferably a bonates containing 1,6-hexane d1ol as the main dlalcohol A in addition to other diols, are particularly suitable for use harm as the dialcohols.

One may use as the diisocyanate component in which X is absent or :N:

one or more of the following compounds: aliphatic, cyclo- -O. CH2, 2- 21 I aliphatic, araliphatic, aromatic diisocyanates and hetero- CH; cyclic diisocyanates. Aromatic diisocyanates of symmetrical structure are particularly suitable examples, including a divalent aralrphatrc radical, preferably a 1,3 or 1,4 p y methane diisocyanate; p y dimethyl methane 4,4 diisocyanate, phenylene-1,4-diisocyanate;

CH2 (OH2)y (CHEM CH2 radical 2,2',-6,6-tetramethyl diphenyl me-thane-4,4'-diisocyanate;

yzo 1, a radical HN CO CO .NH diphenyl l,4 diisocyanate; diphenyl ether-4,4-diisocya- 1 1 C NH i hi nate or their alkyl-, alkoxylor halogen-substituted derivais a divalent organic radical with up to 13 carbon atoms, fives; 9 y Y -d y for example an aliphatic, cycloaliphatic or aromatic thflr commefclal f s P PY p ffyl n radical, preferably a 1,3-d11socyanate, m-xylene dnsocyanate, p-xyleue d isocyamate and a,a,a',a'-tetramethyl-p-xylene diisocyanate. In

mire T I addition one may also use the alkyl or halogen-substituted CH CH3 products of the above-mentioned diisocyanates, for example 2,5-dichloro-p-xylene diisocyanate or tetrachloro-pphenylene diisocyanate, dimenc tolylene-2,4-d11socyanate OH,-N N-orr,- 0H, ,-o0-NH or bis-3-methyl-4-isocyanatophenyl urea. Aliphatic 'diisocyanates such as hexane-1,6-diisocyanate, cyclohexane-1,4- radical diisocyanate, dicylohexylmethane-4,4'-diisocyanate, l-iso Examples of suitable relatively high molecular weight cyanato 3 is0cyanatomethyl-3,5,5-trimethyl cyclohexane substantially linear polyhydroxyl compounds with teror 2,2,4-trimethyl hexane-1,6-diisocyanate, may also form minal hydroxyl groups (or formula HO-DOH) inat least part of the isocyanates used and, following exponate and dicyclohexylmethane:4,4-diisocyanate, are preferably used.

To prepare the substantially linear relatively high molecular weight NC'O-preadducts, the relatively high molecular weight polyhydroxyl compounds referred to above,

are reacted with the diisocyanates in excess molar quantities, for example in a molar ratio of 1: 1.25 to 1:4.0, preferably from 1:1.30 to 1:25, with the diisocyanates optionally added in stages, in the melt or in the solvents inert with respect to isocyanates such as tetrahydrofuran, dioxan, ethyl acetate, butanone-2 or chlorobenzene, dimethyl formamide, at temperatures of from about to 130 C. and preferably at temperatures of from to 100 C. Where the relatively high molecular weight'polyhydroxyl compounds have fairly low molecular weights, for example, from 650 to 1250, the diisocyanates are preferably reacted in lower molar ratios, for example from 1:1.25 to 112.0. They are preferably used in higher molar ratios, for example from 1:15 to 2.5 in cases where they have relatively high molecular weights.

If a polyhydroxyl compound 'OH--DOH is reacted with a diisocyanate OCN-RNCO in a molar ratio of 1:2, and NCO-preadduct with the idealized structure is formed. If the reaction is carried out with a molar ratio of 1:1.5 (=2z4), an NCO-preadduct with the general structure is formed.

To all intents, the same structure is obtained in cases where the polyhydroxyl compounds are initially reacted with an OH/NC'O ratio of 2:1 and the new pre-extended dihydroxy compound subsequently converted into the NCO-preadduct, optionally in conjunction with another diisocyanate, with an OH/NCO ratio of 1:2. With other molar ratios, statistical mixtures of corresponding NCO- preadducts can be formed.

In the preparation of the NCO-pre'adducts, relatively small quantities of low molecular weight diols with molecular weights of from 62 to about 300, in particular those which contain one or more tertiary amino groups, may be used together with the relatively high molecular weight polyhydroxyl compounds HODOH for the reaction with the diisocyanates.

The diols may be added either in admixture with the relatively high molecular weight polyhydroxyl compounds or at any time during or even after the NCO-preadduct has been formed from thediisocyanate and relatively high molecular weight polyhydroxyl compounds. Suitable diols include, for'example, ethylene glycol, 1,4-butane diol, bis- N,N 3- hydroxyethyl)-methyl amine; bis-N,N-(,6-hydroxypropyl) -methyl amine; N,N-dimethyl-N,N-bis(B- hydroxy ethyl)-ethylene diamine; N,N'-dimethyl-N,N'- 'bis-(fi-hydroxy propyl)-ethylene diamine; N,N'-bis-(/8-hydroxy propyl)-piperazine; N,N'-bis-( 8-hydroxy ethyl)- piperazine or hydroquinone-bis-(fl-hydroxy ethyl ether).

Theuse of diols containing tertiaryzamino groupsimproves in particular the aflinity for dyes and'fastness to light of the products and provides a starting point for other after treatments, for example the crosslinking reaction with 4,4'-dichloro methyl diphenyl ether. a

The low molecular weight diols are generally used i quantities of from 0.01 to 1.0 mol and preferably in quantities of from 0.05 to 0.5 mol. They may be used to particular advantage in quantities of from 0.07 to 0.25 mol per mole pf polyhydroxyl compound in the formation of the NCO-preadduct. Inthese cases, the quantity in which the diisocyanate used is preferably increased to beyond the molar ratios which have just been specified by an amount corresponding to'the low'molecular weight diols, for example, by 0.01 to 1.0 mol. This results in theformation of NCO-preadducts with the structure or in the case of pre-extension in the formation of an NCO-preadduct with the structure The typical structural segments of the NCO-preadducts (which may also be termed relatively high molecular weight diisocyanates) which arise out of pre-extension or glycol incorporation, are formed in a more or less statistical sequence and may optionally occur in multiple repetition.

The number of NCO groups present in the NCO-preadducts (calculated as percent by weight of NCO in the solvent-free NCO-preadduct) is of decisive importance to the properties of the polyurethane elastomers obtained from them. Generally speaking, it is only those NCO- preadducts whose NCO content in the solid amounts to at least 1.0%, that are suitable for reactions with the semi-carbazide hydrazides to be used as chain extenders in accordance with the invention. The NCO-preadducts should preferably contain from 1.5 to about 6% by weight of NCO. NCO contents of from 1.75 to 3.5%, based on the solids content of the NCO-preadduct, are particularly preferred in cases where the elastomers ob tained from them are to be used for the production of elastomer filaments.

Aliphatic semicarbazides hydrazides of the formula (x=1 or 2) are used in substantially equivalent quantities, based upon the number of NCO groups in the NCO-preadduct, as the bifunctional chain extenders containing 2 active hydrogen atoms, and are preferably em-v ployed as the sole chain extenders. ,B-Semicarbzizide pro NH -groups of the formula H N-Z--NH in which Z ganic compounds with two' terminal NH groups, such.

is zero or represents a bivalent organic radical with from 2 to 13 carbon atoms.

Examples of suitable conventional chain extenders include water, glycols, amino alcohols or preferably oras hydrazine (or hydrazine hydrate), aliphatic diamines, preferably ethylene diamine, l,2-propylene diamine, cisand/or trans-1,3-diaminocyclohexane, N,N-bis-(y-aminopropyl)-methyl amine; N,N' dimethyl N,N' bis-(yaminopropyl) ethylene diamine; N,N' dimethyl-N,N-' blS (y aminopropyl)-piperazine; N,N' bis (y-aminopropyl) 2,5 dimethyl piperazine, aromatic diamines, preferably 4,4 diamino diphenylmethane; 4,4 diamino diphenyl ether, 4,4'-diamino diphenyl ethane, or' 4,4fd iamino diphenyl dimethylmethane; araliphatic diarnines such, as mor p-xylylene diamine, 1,4-bis-(fi-aminoethyl)- benzene or a,a,a,a'-tetramethyl .p xylylene diamineg or dihydrazides, bissemicarbazidesor bis-carbazine esters such as carbodihydrazide, terephthalic acid dihydrazide, hydroquinone diacetic acid dihydrazide, aminoacet'ic acid hydrazide, methylamino-N,N bis (propionic acid'hydraz ide), I N,N'-piperazine-bis-(propionic acid hydrazide), N,N-dimethyl ethylene diamine-N,N'-bis-(propionic acid hydrazide).

In order to reduce the molecular weight and, in spite of any molecular branching that mayhave occurred, to obtain soluble polyurethane elastomers, it is also possible to use monofunctional compounds in small quantities for chain-terminating reactions for example in quantities of from 0.01 to 10 mol percent (based on the NCO content). Butyl amine, dibutyl amine, acethydrazide, butyl semicarbazide, N,N'-dimet hyl hydrazine may be used for this purpose. I

The NCO-preadducts are reacted with the chain extenders in substantially stoichiometric equivalent quantities (based on the NCO content), for example in quantities of from 100 to 120% and preferably in quantities of from 100-to 110 mol percent of chain extenders, advantageously at temperatures of from about to 130 C. and preferably at temperatures of from 20 to 80 C., in the presence of solvents. The higher the excess of chain extenders, the lower will be the molecular weight of the polyurethane. The required molecular weight and solution viscosity may be adjusted by the careful addition of other preferably less reactive aliphatic dior tri-isocyanates (according to German patent specification No. 1,157,386). After the required viscosity has been obtained, the still unreacted terminal groups may he stabilised by reaction with mono isocyanates such as butyl isocyanate, carboxylic acid anhydrides or other acylating substances such as acid chlorides or carbamic acid chlorides, e.g. acetanhydride, phthalic acid anhydride, acetylchloride.

Suitable solvents in which the process of the invention may be carried out include highly polar, organic watersoluble solvents which contain amide, urea or sulphonic groups, are capable of forming, strong hydrogen bridge bonds and which preferably have boiling points of from about 140 to 225 C., for example dimethyl formamide, diethyl formamide, dimethyl acetamide, N-formyl morpholine, hexamethylphosphoramide, tetramethyl urea, dimethyl sulphoxide, dimethyl cyanamide or mixtures thereof. For commercial reasons, dimethyl formamide or dimethyl acetamide is preferably used as the solvent. Less polar solvents which on their own are not able to dissolve the polyurethanes and polyurethane ureas, for example tetrahydrofuran, dioxan, acetone, ethylene glycol, monoethyl ethe'r acetate or chlorobenzene, may be added to the highly polar .solventsinquantities of up to 33% by weight of the total amount of solvent. The semicarbazidehydrazides are advantageously first dissolved in a minor amount of water (such as twice the weight ofsemicarbazide-hydrazide) and then diluted with the highly polar organic solvents (such as dimethyl formamide). The concentration of the elastomer solutions should amount to between about and 43% by weight, preferably to be tween and 33% and more, preferably to between and 28% by weight, with the viscosities lying between l and 3000 poises/ 'C. and preferably between about 50 and 800 poises/20" C. The molecular weight of the segmented elastomers according to the invention should be so high that the inherent viscosity as measured at C. I 7 I "A I amounts touat least 0.5 and preferably to between 0.70 and ,1.'9 'when;determinedwith a solution of 1.0 g, of elastomer which has :beendissolved in 100 ml. of hexamethyl;phosphoramide (phosphoric'acid tris-dimethylamide) at 20 C. Inthe above equation, 1 is the relative viscosity-(ratio of the through-flow time of the solution to. the through-flow time of the solvent) while C is the concentration in g./100 ml. The melting points of the elastomers, as determined on Kofler'benches, should b above 200 .C.. and preferably above 220 C. in cases where they are to bev used as starting materials for elastomer filaments.

The solutions of the polyurethanes and polyurethane ureas may have added to them organic or inorganic pigments, dyes, optical brighteners, UV-absorbers, phenolic antioxidants, special UV-absorbers such as N,N-dialkyl semicarbazides or N,N-dialkyl hydrazides and crosslinking substances, for example paraformaldehyde, melamine hexamethylol ether or other formaldehyde derivatives such as dimethylol dihydroxy ethylene urea, dimethylol ethylene urea, trimethylol melamine and dimethylol urea dimethyl ether, quaternising agents, for example dichloromethyl durol or polyaziridine ureas, for example hexamethylene-w,w-bis-ethylene imide urea. The resistance to the dissolution and the swelling effect of highly polar solvents is modified for example by using a thermally initiated crosslinking reaction.

The solvent may be removed from the elastomer solutions by a variety of methods known per se, including evaporation or coagulation, in some cases accompanied by formation of the required shaped product such as filaments or foils. Films or coatings are produced by allowing the elastomer solution or dry on substrates, for example glass plates or textile products. Filaments can be obtained by wet or dry spinning. Microporous coatings are obtained by coating elastomer solutions or water-containing dispersions on to (optionally textile) substrates, eventually holding the coated polyurethane in an atmosphere of moist air for some time followed by coagulation in non-solvents for the polyurethane, for example water, organic solvents or mixtures thereof. The microporosity of the films can be increased by use of suitable additives such as finely divided salts, emulsifiers or soluble polyamides.

The parts indicated in the following examples are always parts by weight unless otherwise stated.

The films and filaments referred to in the examples were prepared and measured by the following standard processes: I

Films: By brushing the elastomer solution on to glass panels and allowing it to dry (30 minutes at C., +45 mins. at 100 C.), final thickness from about 0.15 to 0.25 mm. Some filaments of from about 250 to 800 den. thick were cut out of the films by means of a film-cutting machine and measured.

Wet spinning process: An elastomer solution, preferably of 20% by weight concentration is spun at a rate of about 1 ml./min. through a 20-hour spinnerette (bores 0.12 mm. in diameter) into a coagulating bath heated to -85 C. of by Weight of water/ 10% by weight of dimethyl formamide (length approximately 3 m.), and wound up at a take off rate of 5 m. per minute after passing through a washing zone (water/90 C.). The bundles are stored in boiling water (50 C. for 1 hour) and then dried.

Dry spinning process": A preferably 24 to 26% by weight elastomer solution is spun through a 16-hole spinnerette (bore-diameter 0.20 mm.) into a shaft 5 m. long heated t0"220-250 C. into which air heated to between 210 and 280 C. is blown. The filaments are run off at a rate of about m..per minute and, following treatment with a talcum suspension, optionally accompanied by stretching, are wound up for example at a rate of to m. per minute. The filaments may then be heat treated either while on bobbins or in continuous form.

1 1 Elongation at break is measured in a tensile testing machine. The distance between the grips is monitored by a light barrier, and the amount of slip duly compensated. In the elasticity data which is given below, the modulus at 300% is shown in the first elongation curve, the modulus at 150% in the third recovery curve, whilst the permanent elongation is determined after three times 300% elongation, 30 seconds after relaxation.

The heat distortion temperature (HDT) of elastomers is determined as follows: The denier of elastomeric filaments laid out for some 3 hours under normal climatic conditions completely free of tension, is determined by weighing a 450 mm. long length of filament under an initial strain of 0.05 m-g./ den.

An elastomeric yard is suspended at room temperature in a tube which contains air or is filled with nitrogen, under an initial load of 2 mg./den., the distance between the grips being 250 mm. The tube is surrounded by a heating jacket through which flow a silicone oil heated and with its temperature thermostatically controlled. The temperature inside the tube is first of all increased to about 125 C. over a period of about 30 minutes. Thereafter, the temperature is increased at a rate of 3 C. every 5 minutes until the elastomeric filament has undergone a change in length of more than 400 mm. The measurements obtained are plotted in a graph in such a way that on the abscissa 1 unit of length corresponds to a temperature difference of C. whilst on the ordinate 1 unit of length corresponds to a change in length of the elastomeric filament of 20 mm. The heat distortion temperature (HDT) is the temperature read off by vertically projecting the point of contact of the 45 tangent to the temperature/ length change curve on the abscissa.

In general, the resistance of the elastomers to heat may be more highly assessed, the higher the I-IDT-value which is found. For high grade elastomer filaments, the value should amount to at least 145 C. and preferably to higher than 150 C. 0

Determining the hot-water-induced decrease in tension (HWDT) of elastomeric filaments is carried out as follows:

A length of filament held between grips 100 mm. apart is stretched by 100% at a temperature of 20 C. and the tension (mg/den.) produced in it after 2 minutes is measured (first value). The filament still stretched by 100% is then immersed inwater heated to 95 C. and the tension produced after a residence time of 3 minutes is measured (second value). After this measurement, the filament is removed from the water bath and left for 2 minutes at room temperature. The filament still held between the grips is then released until free of tension and the permanent residual elongation measured (third value).

Plan of the reproduction in the examples (abbreviation HWDT):

1st value-Strain value in air at 20 C. (mg./ den.)

2nd value-in water at 95 C. (mg./ den.)

3rd value-Residual elongation after relaxation (in air) at 20 C. (percent) This hydrothermal properties may be assessed more accurately, the greater the second value (tension in hot water mg./den.') and the smaller the third value (residual elongation after treatment in the relaxed state). The strain value in water should amount to at least mg./ den. and to more than mg./den. in the case of high grade elastomer filaments. After hydrothermal treatment, the residual elongation in the relaxed state should be less than 45% and preferably less than 40%. Determination the hot water elongation (HWE) of elastomeric filaments is carried out as follows:

A weight of 30 mg./den. is attached by means of a clip through a 50 mm. long filament, and is left suspended in air for 25 minutes at room temperature. After 25 minutes, the percentage elongation is determined (first value). The filament thus elongated is then immediately immersed in water heated to C. together with the weight attached to it and the elongation occurring under water is read off after an interval of 25 minutes. It is expressed as percentage elongation based on the distance between grips 50 mm. (second value). The weighted filament is then removed from the hot water bath, after which its permanent residual elongation is determined by lifting the weight until the filament is free of tension (3rd value).

Plan of the reproduction in the examples (abbreviation HWE):

1st value: Elongationin air at 20 C. percent 2nd value: Elongationin water at 95 C. percent 3rd valueResidual elongation (after relaxation in air at 20 C.) percent This hydrothermal properties may be assessed more highly, the smaller the second value (elongation in hot water) and the smaller the third value (permanent elongation after relaxation). For high grade elastomer filaments, the second value should be less than 250% and preferably less than 150%, whilst the residual elongation (third value) should be less than 150% and preferably less than The melting point of the elastomer substance is measured on a strip of film after it has been placed for a period of 2 minutes on a Kofier bench, and should be above 200 C. and preferably above 230 C. for elastomeric filaments.

In order to determine the inherent viscosity 1 samples of the elastomeric substance (films) are dissolved in a concentration of 1.0 g. of elastomeric substance per 100 ml., in hexamethylene phosphoramide at room temperature, and the relative viscosity 7 Flow out time of the solution nR- Flow out time of the solvent (C=concentration in g./100 ml.)

Preparation of the new semicarbazides:

(1) u-semicarbazide acetic acid hydrazide:

parts of phenylchlorocarbonic acid ester are dissolved in 500 parts by volume of methylene chloride. The solution is cooled to 05 C. and Y100 parts of water are poured over it.

139.5 parts of solid glycine ethyl ester, hydrochloride are introduced in portions and at the safe time a solution of 56 parts of potassium hydroxide, 80 parts of potassium carbonate and 25 parts of potassium hydrogen carbonate in 300 parts of water is added dropwise over a period of 30 mins. The 2-phase reaction system is then stirred for another 2 /2 hrs. Without cooling, the phases separated, the methylene chloride solution dried over anhydrous sodium sulphate and finally the methylene chloride is dishydrate in 250 parts by volume of ethanol, and the reaction solution is kept boiling for 1% hours. After the reaction solution has cooled to C.,.the white crystals precipitating in large quantities are filtered under suction, washed with alcoholand dried. The semicarbazide acetic hydrazide is obtained in a crude yield of 91% of the theoretical. After recrystallisation from alcohol (2 ml./ g.) and water (1.5 ml./g.), pure colourless crystals are ob taine'd'in a yield of 71%, M.P. 167 C.

C N NO (molecular weight 147). Calculated (percent) N, 47.6. Found (percent): N, 47.5.

(ii) fl-semicarbazide propionic acid hydrazide:

712 parts of fl-alanine are added into 920 parts by volume of'alcohol. 400 parts of hydrogen chloride are introduced begining at 20 C.' and progressing with rapid heating to boiling point (20 minutes): the mixture is kept boiling for a period of 2 hours. After some 1% hours, the suspension has become a clear solution. On completion of the dissolution, 460 parts by volume of benzene are added in order to azeotropically distill off the water of esterification. Finally, the residual alcohol is distilled ofi', ultimately in vacuo (15 mm. Hg). The ester/HCI salts is obtained as an oil in a quantitative yield. The oily crystallises on standing or a vigorous cooling.

1180 parts of phenyl chlorocarbonic acid ester are dissolved'in 3800 parts by volumeofmethylene chloride, and 700 parts of water are added torthe resulting solution whichis then cooled to 07 C. 1228 parts of fl-alanine ethyl ester hydrochloride are added dropwise into the twophase system from a heated dropping funnel, a solution of 450 parts of potassium hydroxide and 1090 parts of potassium carbonate'in 2600 parts of Water being simultaneously run in. The dropwise addition takes about 60 minutes to complete. The two-phase system is then stirred for 2 /2 hours without cooling, the phases are separated, the methylene chloride solution is dried over anhydrous sodium sulphate and finally the methylene chloride is distilled off. The fl-carbethoxy ethylene carbamic acid phenyl 'ester is-an oil which crystallises after prolonged standing, M.P. 63 C., yield approximately 75% of the theoretical.

A solution of 1336 part of pcarbethoxy ethylene carbamic acid phenyl esterin 800 parts by volume of alcohol is introduced over a period of approximately 30 minutes into a boiling solution of 1900 parts of hydrazide hydrate and 480 parts by volume of alcohol. After boiling for 1% hours, the solution is cooled to 0 C., the crude ,B-semicarbazidopropionic acid hydrazide which has crystallized out is quickly filtered under suction and the filtrate is suspended in alcohol and is then sharply suction-filtered again. After drying, the crude yield amounts to 872 parts (965 of the theoretical). Recrystallisation from water (0.9 ml./ g.) and alcohol (2.0 ml./ g.) gives 628 parts or 72% of the theoretical of pure fl-semicarbazido propionic acid hydrazide, M.P. 163164 C.

C H N O (molecular weight 161). Calculated (percent): N, 43 .46. Found (percent): N, 43.45.

The following examples illustrate more particularly the invention.

Example I 1200 parts of a mixed polyester of adipic acid and a glycol mixture of 1,6-hexane diol/2,2-dimethyl propane diol in a molar ratio of 65:35 (OH number 68.0, M.P. 34-36 C.) are heated for 53 minutes to 9296 C. with 23.55 parts of N,N-bis-(,8-hydroxy propyl)methylamine, 335.4 parts of diphenyl methane-4,4-diisocyanate and 389 parts of chlorobenzene, and the resulting mixture is left to cool to room temperature. The NCO-preadduct solution has an NCO content of 1.9%=2.38% of NCO in the solid).

400 parts of the above NCO-preadduct solution are stirred within a matter of minutes into a solution heated to C. of 14.85 parts of fl-semicarbazide propionic acid hydrazide in 985 parts of dimethyl formamide, resulting in the formation of a moderately viscous elastomer solution whose viscosity is increased by the addition of 12 parts of another NCO-preadduct. After pigmenting with 4% TiO' the viscosity amounts to 855 poises/20 C.

Part of this solution is spun by the dry spinning process (cf. general procedures) and, after dilution to 20% another part is spun by the wet spinning process to give elastomeric filaments Whose properties are set out in Table I and compared with the results from comparative tests. The elastomeric filaments do not show any signs of discolouring after 1 hours immersion in or brief boiling in ammoniacal CuSO solution.

The inherent viscosity of the elastomer subtance is 1.27, and its melting point (Kofler bench) 230 C.

Comparative tests.-The structurally most similar dihydrazide/ or bissemicarbazide chain extenderszsuccinic acid dihydrazide (a) and ethylene bis-semicarbazide (b) and carbodihydrazide (0) preferably used as chain extender for elastomeric filaments, are used for comparison, together with the NCO-preadduct that was used as described above for extension with fl-semicarbazide propionic acid hydrazide.

Comparative test (a) succinic acid dihydrazide.--40O parts of the NCO-preadduct solution of Example I (1.9%) are reacted in a solution heated to approximately 70 C. of 14.2 parts of succinic acid dihydrazide in 922 parts of dimethyl formamide to form a moderately viscous elastomer solution whose viscosity increases following the addition of another 28.5 parts of NCO-preadduct. After pigmenting with 4% of TiO the solution has a viscosity of 610 poises at 20 C. It is then spun into elastomeric filaments as described in the preceding example (see Table 1 for results). The solid elastomer has a melting point of 224 C.

Comparison test (b) ethylene bis-semioarbazide.-400 parts of the NCO-preadduct solution of Example I (1.9% NCO) are introduced into a solution heated to 70 C. of 16.24 parts of ethylene bis-semicarbazide in 928 parts of dimethyl formamide. A non-uniform solution is obtained after only about half the pre-adduct has been added, turning into a stiff, crumbly mass as more preadduct is added (inadequate solubility of the elastomer). The paste cannot be spun or shaped. Even when N-methylpyrrolidone is used in place of dimethyl formamide it is not possible to obtain 'a solution, even with fairly strong dilution to a solids ocntent of 20%. It is not possible to conduct any spinning tests, nor is it possible to obtain uniform films.

Comparative test (0) carbodihydrazide-400 parts of the NCO-preadduct solution of Example 1 (1.9% NCO) are introduced into a solution heated to 70 C. of 8.76 parts of carbodihydrazide in 907 parts of dimethyl formamide, resulting in the formation of a moderately viscous elastomer solution. Following the addition of 23 parts of more NCO-preadduct and pigmenting with 4% TiO the viscosity of the elastomer solution increases to 645 poises/ 20 C. It is spun as described in Example 1, the results being set out in the following table.

The filaments turn dark-red-brown in colour following treatment with amomniacal CuSO solution.

creased to 556 poises following the addition of 0.29 part of p,p'-diisocyanate dicyclohexylmethane. The solution is pigmented with 4% TiO' (based on the solids content) and converted in the usual way into films or into filaments by dry or wet spinning. The solid elastomer has an inherent viscosity of 1.12. Both the thermal and the hydrothermal properties are excellent. The filaments do not undergo any decrease in strength under the normal conditions of hydrolysis (of. Example 1), and have a melting point of from 227-228 C.

Example 6 500 parts of the NCO-preadduct solution described in Example (1.73% NCO) are stirred over a period of 20 minutes into a solution heated to 65 C. of 15.50 parts of semi-carbazide acetic acid hydrazide in 891 parts of dimethyl formamide. After cooling, a uniform colourless elastomer solution with a viscosity of 189 poises is obtained. This is given a pigment content of 4% by the addition of TiO The viscosity rises to 561 poises after the addition of 15 parts of more NCO-preadduct solution. The elastomer has an inherent viscosity of 1.06.

The results of tests conducted on films and filaments are set out in Table 5. Both the thermal properties and the hydrothermal properties of the filaments are clearly less favourable than if they had been similarly extended with the homologous B-semicarbazide propionic acid hydrazide (of. Example 5). Thefilaments have a melting point of 223 C.

Example 7 300 parts of a commercial caprolactone polyester with a molecular weight of 830 and a melting point of 38-40" C. (a product of the Union Carbide Company known as MAX 520) are heated for 50 minutes to 94-95 C. with 6.55 parts of N,N-bis-(B-hydroxy propyl)-methyl amine, 124.3 parts of diphenyl methane-4,4-diisocyanate and 185 parts of chlorobenzene. The resulting NCO-preadduct solution is then cooled to room temperature after which it contains 1.21% of NCO (corresponding to 1.725% of NCO in the solid substance 12.5 parts of fi-semicarbazide propionic acid hydrazide are dissolved in 882 parts of hot dimethylformamide. 500 parts of the above NCO-preadduct solution are stirred over a period of 10 minutes into this approximately 50 C. solution, resulting in the formation of a high viscosity homogenous elastomer solution. Following dilution with 51 parts of dimethylformamide and the addition of 4% of TiO (based on elastomer substance), the elastomer solution has a viscosity of 660 poises. The elastomer has an inherent viscosity 1;, of 1.26.

The data set out in Table 5 are obtained by casting the solution into films and spinning it in dry and wet spinning tests. The filaments obtained show outstanding hydrothermal properties. These elastomer filaments show a high resistance to hydrolysis. There is no decrease in tensile strength after hydrolysis for 16 hours in a washing solution of 2 g. per litre of soda and 5 g./I of soap heated to C.

Example 8 parts of a linear polycarbonate (OH number 122.5, molecular weight 915, melting point about 3035 C.), prepared by the high temperature condensation of diphenyl carbonate and a mixture of the diols 1,6-hexane diol and B-hydroxy ethoxyl-1-hexanol-6, in a molar ratio of 3:1, are first dehydrated and then heated with 9.5 parts of tolylene diisocyanate (commercial isomeric mixture 65:35) for 30 minutes to a temperature of 100 C. After the polyhydroxy compound has been dissolved in 100 parts of chlorobenzene, the resulting solution is heated for 30 minutes to 100 C. with 23.2 parts of 4,4'-diphenyl methane diisocyanate. The NCO prepolymer solution has an NCO content of 1.40% (NCO content of solid: 2.46% 5.60 parts of ,G-serniearbazide propionic acid bydrazide are dissolved at 70 C. in 400 parts of dimethyl acetamide. 200 parts of NCO prepolymer solution poises/20 C.) are run into this solution with stirring. The 18.9% viscous solution is pigmented with rutile (4% based on elastomer content) and is cast into films or wetspun to form elastic filaments. The results of tests conducted on films and the results of tests on the wet-spun products are set out in Table 5. Graves tear propagation resistance as measured on films, amounts to 30 kg./cm., and microhardness to 65. The elastomers have a melting point of 230 C.

Example 9 100 parts of the above-described polycarbonate are preextended -With 9.5 parts of tolylene diisocyanate, and then, following the addition of 100 parts of chlorobenzene, are reacted with 21.1 parts of 4,4'-diphenyl methane diisocyanate to form the NCO prepolymer. The solution has an NCO content of 1.20% (NCO content, based on solids content=2.l8%).

4.80 parts of fl-semicarbazide propionic acid hydrazide are dissolved in 400 parts of dimethyl formamide and, as already described, the resulting solution is reacted with 20 parts of NCO prepolymer solution and the product of this reaction is cast into films or wet-spun into filaments (cf. Table 5).

Example 10 100 parts of a mixed polyester of 1,6-hex-ane diol and 2,2 dimethyl 1,3 propane diol (molar ratio of the glycols=65 :35) and adipic acid, with a hydroxyl number of 66 (molecular weight 1700) are dehydrated, following the addition of 0.1 part of a 33% solution of sulphur dioxide in dioxane C./l hr./ 15 mm. Hg). Following the addition of 2.0 parts of N,N-bis-(,8-hydroxy propyl)-methyl amine and 5 parts of chlorobenzene, the hydroxy compounds are heated for 45 minutes to 100 C. With 28.5 parts of 4,4-diphenyl methane diisocyanate. The NCO prepolymer melt is dissolved in 95 parts of chlorobenzene. The solution has an NCO content of 1.40% (corresponding to 2.4% in the solid NCO prepolymer).

200 parts of the NCO prepolymer solution are run in with stirring at 80 0., into a solution of 5.70 parts of fl-semicarbazide propionic acid hydrazide in 300 parts of dimethyl sulphoxide, and 20 parts of dimethyl sulphoxide are added to the resulting solution. The 22.5% high viscosity elastomer solution obtained is pigmented with 4% of rutile (based on the solids content) and is cast into films or wet-spun into elastic filaments. The results are set out in Table 5. The tear propagation resistance of films (according to grades) amounts to 55 kg./cm., and the micro hardness of films to 64. Filaments left in ammoniacal copper sulphate solution (0.01 of normal) remain white in colour.

Comparative test (e).100 parts of the mixed polyester used in Example 1 (molecular Weight 1700') are first dehydrated and then admixed with 2.0 parts of N,-N' bis (p hydroxy propyl) methyl amine and 5 parts of chlorobenzene, and the resulting product is heated for 50 minutes to 100 C. with 29.2 parts of 4,4-diphenyl methane diisocyanate. The NCO prepolymer is diluted with 95 parts of chlorobenzene, the solutionwhich has a solids content of 50%, has an NCO content of 1.38% (corresponding to 2.51% of NCO in the solid NCO-preadduct).

605 parts of 'y-semicarbazide-butyric acid hydrazide (from C H O-CO-NH(CH CO OCH +hydrazine hydrate, M.P. 102 C.) are dissolved at C. in 300 parts of dimethyl formamide. 200 parts of NCO prepolymer solution are run into this hot chain extender solution with thorough stirring, followed by 20 parts of dimethyl formamide. The elastomer solution is then quickly cooled to room temperature. Films and filaper se.

21 Example 11 l50 parts of the copolyester used in Example 1, which has an OH number of 68 and 37.2 parts of 4,4'-diisocyanato-diphenyl ether are heated for a period of 45 minutes to temperatures between 90 and 98 C. in a boiling water bath with 47 parts of chlorobenzene. After cooling to room temperature, the NCO-preadduct solution has an NCO content of 0.816%.

104.5 parts of the NCO-preadduct solution are introduced with intensive stirring into a solution of 4.15 parts of fl-semicarbazide propionic acid hydrazide in 232 parts of dimethyl formamide, resulting in the formation of a' high viscosity elastomer solution which, following dilution with dimethyl formamide to a solids content of 20%.has a viscosity of 206 poises at 20 C. After casting into films and cutting into filaments, the elasticity properties are determined. Elastorneric filaments with outstanding (hydro) thermal properties are spun by the standard wet-spinning method (cf. Table 5). The elastomers have a melting point of 244 C.

Example 12 14.7 parts of a-semicarbazide acetic acid hydrazide are dissolved at 100 C. in 1092 parts of dimethyl formamide and the resulting solution is mixed at 60 C. with 356 partsv of the 'NCO-preadduct melt of Example 4, the resulting mixture being homogenised by stirring. The solution is pigmented with 4% of "H (based on the solids content). 1.02 parts of 1,6-hexane diisocyanate and another 80 parts of dimethyl formamide are added to the viscous solution producing 'an increase in viscosity to 874 poises at 20 C.

After the solution has been cast into films, the elasticity properties of the films are measured on cut filaments. As the results show (Table outstanding strength and elastic properties are obtained. The filaments obtained by wet-spinning tests (or dry-spinning tests), however, only show moderate thermal and hydrothermal properties (compartive test and Example 4). The elastomer substance does not show any signs of discolouration when boiled in tap water or after immersion for 5 minutes in 0.01 molar ammoniacal copper sulphate solution heated to 60 C. The elastomer has a melting point of 213 C.

Example 13 800 parts of a mixed polyester of adipic acid and a mixture of ethylene glycol and 1,4-butane diol (molar ratio of the glycols 1:1), molecular weight 1980, melting point 33-37 C., are reacted for 100 minutes at 80 C. with 192 parts of diphenyl methane-4,4-diisocyanate and 174 parts of chlorobenzene to form 'a NCO-preadduct. The solution has an NCO content of 2.56% (3.1%- of the NCO in the solid).

1 00 l parts of the NCO-preadduct solution are stirred into a solution heated to 70 C. of 4.92 parts of B- semicarbazide propionic acid hydrazide and 0.092 part of N,N-dimethyl hydrazide in 255 parts of dimethyl formamide, resulting in the formation of a highly viscons. slightly hazy solution. Following dilution with dimethyl formamide to a concentration of 20% (viscosity 480 poises), films are prepared in the usual way, and filaments are obtained by wet-spinning. The solid elastomer shows improved resistance to light and oxidation and has a melting point of 230 C.

Example 14 22 Example 15 3.97 parts of B-semicarbazide propionic acid hydrazide are dissolved at 70 C. in 255 parts of dimethyl formamide and the resulting solution is mixed with 1.12 parts of m-xylylene diamine (molar ratio of the chain extenders 75 :25 103.5 parts of the NCO-preadduct solution described in Example 13 are introduced into this solution over a period of 4 minutes to form a homogenous highly viscous solution (450 poises/ C.). The elastomer solution is converted in the usual way into films or filaments (see Table 5 for results). The elastomer has a melting point of 237 C.

Example 16 107.5 parts of the NCO-preadduct solution used in Example 13 are introduced into a solution of 3.7 parts of fl-semicarbazide propionic acid hydrazide and 1.98 parts of 4,4'-diamino diphenyl ether (molar ratio of the chain extenders 70:30) in 259 parts of dimethyl formamide. The resulting highly viscous elastomer solution is diluted with dimethyl formamide to a concentration of 20% (160 poises), and then converted into films and filaments (see Table 5 for results). The elastomers have a melting point of 250 C., with softening from 241 C.

Example 17 1000 parts of the mixed polyester in Example 1 (hydroxyl number 67.4), 19.5 parts of N,N-bis-(/8-hydroxy propyl)-methylamine, 273.2 parts of diphenyl methane- 4,4'-diisocyanate and 327 parts of chlorobenzene are heated for 35 minutes to an internal temperature of 90- 99 C. After cooling, the NCOpreadduct solution has an NCO content of 1.93%.

3.78 parts of fl-semicarbazide propionic acid hydrazide are dissolved in 230 parts of dimethyl formamide and the resulting solution is admixed with 0.075 part of ethylene diamine in 32 parts by weight of dimethyl formamide (molar ratio of the chain extenders 95:5). 104 parts of NCO-preadduct solution are added to this solution with stirring resulting in the formation of an elastomer solution having vicosity of 315 ipoises at 20 C. The solution is converted into films or, after dilution to 20% poises), is wet-spun into filaments. The results are set out in Table 5. Melting point 228 C.

Example 18 3.18 parts of B-semicarbazide propionic acid hydrazide are dissolved at 70 C. in 200 parts of dimethyl formamide and the resulting solution is admixed with 1.00 part of N,N'-bis-('y-amino propyl)-piperazine in 32 parts of dimethyl formamide (molar ratio of the chain extenders 80:20). 104.5 parts of the NCO-preadduct solution used in Example 17 are mixed in with intensive stirring, resulting in the formation of a homogenous colourless solution with a viscosity of 255 poises. The results of tests conducted on films and filaments are set out in Table 5. The product shows a high affinity for acid dyes with which it can be dyed fast.

Example 19 3.58 parts of B-semicarbazide propionic acid hydrazide and 0.64 part of piperazine-N,N-bis-(propionic acid hydrazide) are dissolved in 232 parts of dimethyl formamide (molar ratio of the chain extenders=:10). 104.5 parts of the NCO-preadduct solution of Example 17 are introduced into this solution at 65 C. After the viscous solution has been diluted with dimethyl formamide to 20% concentration, films and filaments are obtained by wet-spinning from the solution (50 poises/ 20 C.) in the usual way, cf. Table 5.

Example 20 1000 parts of the polyester used in Example 1 (molecular weight 1655), 18.0 parts of N-N-bis-(fl-hydroxy propyl)-methylamine, 163.6 parts of p-phenylene dig 2mm mm u 2 N ww m5 2 2 8H 2% an d vw 3m ow mw m om 9 m3 2 cm 2: 3 mm Q 2 2. 3; we um Nd" m mw HS 2 mm m2 @mm vw o E 8 33 m2 2 mm c2 m5 and 3&3 u gm I! NB 3 3 ma wan 3 NB 3 mm 2: NE Ed 3 mm :5 93 I B om DH a? mud B 3 w 3 med 8 wow mm a b 2 w 9 N2 2 mm SH c6 aw c -....21--51.-.1.1.1.1-..Iii-{.2212}-.- 2 8 mm ER. 36 i. m3 mm 3 m E m 2 v3 1. mm mm mfi omw cad 4 w 0353 2 3 5 5.63 mm" mmm H. m w 2 HQ 3; S 8 S: Q? Ga 0 $3205 3 mm w: mm mm d E EA EE m 3H 2. a m mm m 8 3 8 mm m2 m3 mm c 5 E cu m2 fig vm o 83 5B E 3 32 .M 3 m w m 3 c2 2 A8 33 25 o m a m Q Q EE V M135 2552a 1 mm 3 3. 3v 3 d m aQm aQEo 3 Q3 2 cm wmfi mmm E 0 .Z 3 I am ow mow cwv w c .m I m E. w: wm cm @m 8 E. o m 5 w QE GE 2 M 3 $2 2 mm 2: Q2 Q8 2W 352 E EE -i- 1...... 2 mm m5 mud m 255mm 5 E2 .563 MQEQQSQ m3 mvm 3 E h 5 m 8 mm: mm mm NE man 2. 0 Z E EA EE M: m c2 mwm 2.5 h d we I. o2 M3 mm whwm w 3 m: a va QB wmm mm o 2 v M: E Q: wmw 36 m 2:... ........m 565 283 0 3 333 033 6&2 5Q&E dwgma A0 L 533 :oE mE QQQ ME 533 5E m mmwuohm Q oaflwwm 0 com 5 5 GB 0 ca 54 fi fi u a O 0mm 6 cow E4 HEW KSmXm -83 E xaom 23 53 b E5323 .52 53% 53 caswwco w .2259: wm wfim 258 QE 3 w qo am QBo ngwwm amwmnfikwm um N B L83 sgwmvm lll||||||l IIIIIII'II I 5 c2335 am 5 532 EQBW 3522 wwsu oa EB Ewmn 95 62 m wnoa 832mm 83 aw: 2: 5 25 8 5255 5 QEQU mm 55 8 05 @56 8 ca 028 0o 0? 0 E2 3 E E E E 83 0 com 2 mu o mm 8 qo bm 05 0o 5%03 0% E @3205 an w -n03 628x58 1338 we m g no 5 0 Nu ia 8 @8305 O Q E EQ-Q 00 53 3 we 0 o fio gxoamm 9 v 3: aowiow m 88 uuosuo 05 5:58 290 2 96p 2: 0 3m 0 Rw4 o 3 :8 002 a mg 25 8:38 5 330 25. 652 80 0 mo 53 E v cguommu iv $5 05 au fiwmo 85m v 5: o mou ow m was 058 {388-2305 \nxokgniv zi 00 53 3 5g 0 owm mw 8 on 0 v 8m SEN E E S UEQEV 3% onmmoa mli ogw-nd we mt ow E8 258m 00 023 E ow mo 25x1: 3% m 28 ox 23 00 $3920. &8 m 0 53 cow 0 03m S 52 m E 0 LC M 353383 qomtow w no: nw E2553 EN 30% 58 -w 95. $3 3: 2w 5 Q33? 2 2.5 8:335 v28 $3 0o coum coucou m 8 Q EQEE 3 06: H B 32 mm 0 oswowmom 33 E528 580320 25. ogs v.8 oumc uowmw q o xoa 00 3 om 5 5 9050 20 8 no 583 2 0 @v 553, 2 5538 @5252 05 62895 E QE we mt m E Q NE F 22 2.8305 u Nm-2E3i 0 .5% 42 o mou ow m 5 0 o 3 woosuo 0E flownow 3% 39002 26mm 2: mo 5% o; A mwfi c0338 woauwsoa 05 o 30300 0076 B EQQE E08 8 203 was 0 mm wm 8 8358 cm .50 32 2m 335920 0 00 H3 mg 9.3 wflfioo 25 What we claim is: 1. A linear segmented polyurethane elastomer consisting of a reaction product of essentially linear, relatively high molecular weight NCO-prepolymers with chain extenders, comprising at least 55%, based on all the chain extending segments present, of a chain extending segment with the structure wherein x is 1 or 2.

2. A linear segmented polyurethane elastomer having an elongation at break of more than 300% and an inherent viscosity of at least 0.5 as measured on a 1% solution in hexamethyl phosphoramide at 25 C., comprising intralinear segments of the structure wherein D represents a long chain divalent aliphatic polymer radical having a molecular weight of from 600 to 5000 and a melting point below 60 C.; R represents a divalent organic radical of an aromatic, aliphatic, cycloaliphatic or araliphatic diisocyanate; G represents a divalent aliphatic, cycloaliphatic or araliphatic radical of a dihydric alcohol with a molecular weight of from 62 to 300, optionally containing 1 or more tertiary aliphatic amino groups; r is an integer of at least 1; s is Zero or an integer of at least 1; x is 1 or 2; m is an integer of at least 1 and 11 an integer of at least 1.

3. A process for the production of substantially linear segmented polyurethane elastomers by reacting a NCO- preadduct containing from 1.0 to 6.0% by weight of NCO, prepared from relatively high molecular Weight dihydroxy compounds having a molecular weight from -600-5000 and a melting point below 60 C. and excess molar quantities of organic diisocyanates, with substantially equivalent quantities of bifunctional low molecular weight chain extending agents containing two hydrogen atoms in the presence of highly polar organic solvents, followed by removal of the solvents, the improvement comprises reacting aliphatic semicarbazide hydrazides of the formula wherein x is 1 or 2, as chain extenders.

4. The process as claimed in claim 3, wherein in addition to at least 55 mol percent of the aliphatic semicarbazide hydrazide up to 45 mol percent of conventional bifunctional compounds with at least two active hydrogen atoms and with molecular weights of about 18 to 300, are reacted as chain extenders.

5. A process for the production of substantially linear segmented polyurethane elastomers by reacting an NCO- preadduct, containing from 1.0 to 6.0% by weight of NCO groups, prepared from relatively high molecular Weight hydroxy compounds and low molecular weight diols with molecular Weights of from 62 to about 300, preferably containing tertiary amino groups in the molecule, in quantities of from about 0.01 to 1.0 mol per mol of relatively high molecular weight dihydroxy compound, and excess molar quantities of organic diisocyanates, with substantially equivalent quantities of bifunctional chain extenders containing two active hydrogen atoms in highly polar organic solvents, followed by removal of the solvents, the improvement comprises using aliphatic semicarbazide hydrazides of the formula wherein x is 1 or 2, as chain extenders.

6. The process as claimed in claim 5, wherein in addition to at least 55 mol percent of the aliphatic semicarbazide hydrazides up to 45 mol percent of conventional chain extenders are reacting.

7. Highly elastic polyurethane elastomer filaments having a breaking elongation of at least 300% and a heat distortion temperature above 145 C., consisting of linear segmented polyurethane elastomers with an inherent viscosity (as measured on a 1% solution in hexamethyl phosphoramide at 25 C.) of at least 0.5, containing intralinear segments with the structure in which D represents a long chain divalent aliphatic polymer radical having a molecular weight of from 600 to 5000 and a melting point below 60 C.; R represents a divalent organic radical of an aromatic, aliphatic, cycloaliphatic or araliphatic diisocyanate; G represents a divalent aliphatic, cycloaliphatic or araliphatic radical of a dihydric alcohol with a molecular weight of from 62 to 300, optionally containing 1 or more tertiary aliphatic amino groups; x is l or 2; r is an integer from 1 to 5; s is zero or an integer from 1 to 5; m is an integer from 1 to 5, preferably from 1 to 3 and n is an integer from 1 to 5.

8. A spinning solution of polyurethane elastomers containing from 10 to 33% by Weight of substantially linear segmented polyurethanes with intralinear structures of a chain extending segment having the formula wherein x is 1 or 2, in a highly polar aliphatic solvent having amide, urea or sulphoxide groups and a boiling point of up to 225 C.

9. The polyurethane of claim 1 wherein x is 2.

10. The polyurethane of claim 2 wherein x is 2.

11. The process of claim 3 wherein x is 2.

12. The process of claim 4 wherein x is 2.

13. The process of claim 5 wherein x is 2.

14. The process of claim 6 wherein x is 2.

15. The polyurethane filament of claim 7 wherein x is 2.

16. The spinning solution of claim 8 wherein x is 2.

References Cited UNITED STATES PATENTS 3,149,998 9/1964 Thurmaier 260- TNH 3,305,533 2/1967 Thoma 260-326 N 3,377,308 8/1968 Oertel 260-326 N 3,432,456 3/ 1969 Oertel 26032.6 N 3,461,106 8/1969 Oertel 260 --77.5 SP 3,467,626 9/1969 Negishi 260'77.5 AM 3,499,872 3/1970 Thoma 260-32.6 N

MORRIS LIEBMAN, Primary Examiner P. R. MICHL, Assistant Examiner U.S. C1. X.R.

260-306 R, 32.6 N, 75 NH, 77.5 AM, 77.5 SP, 554

UNITED STATES PATENT OFFHJE QERTEFICATE OF CQRRECTKON 1 Patent No. 3,7640 Dated Februarv 8 1972 Inventor(s) el et a;

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

COLUMN LINE ERROR I 1 After "Abstract Of The Disclosure" pa paragraph --DISCLOSURE SHOULD HAVE BEEN INSERTED Table 1 Line 50 "-R-NH-CO should be s m I 5 Y Table Line 10 "CO NH-R-NH-CO should be CO NH-R-NH-Co 5 P040510 (10-59) uscoMM-pc scan-poo I 9 U.S. GOVERNMENT PRINTING OFFICE? I959 0-365-33 Paw-Qt 3,640 ,937 Dated February 8 1972 Inventor(s) Oertel et a1 PAGE 2 It is certified that error appears in the above-identified patent and. that said Letters Patent are hereby corrected as shown below:

COLUMN LINE 5 Formula l Line 30 (23) should be 5 Formula I Line 61 "NH-CONH-R"-NH- should be -HNCONHR"NH 7 40' (=2=4) should be (=2=3) 8 52 "substantially equivalent" should be substantially stoichiometrically equivalent :"ORM PO-105l7 (10-69) uscoMM-Dc scan-P69 U.S. GOVERNMENT PRINTING OFFICE: I989 0-366-334 UNITED STATES PATENT OFFICE QERTEFECATE 0F CURRECTEQN Patent No. 0 ,937 Dated February 8, 1972 Inventofls) Oertel t al E 3 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

COLUMN I LINE ERROR 8 74 and N,N"-dimethylN,N'-bis" 75 should be N,N'bis 10 33 solution or dry: should be solution to dry l2 73 "Carbethoxyoxy" should be carbethyoxy 1? 10 "C N N O should be --C H N O 16 a Comp Ex d Line 4 'hydraxine" should be hydrazine 17 Example 4 "Example 4 should follow paragraph it now heads 18 Table 4 "Fitness ,Den" should be Fineness den 2 3 4 165%) should be 1.65%)

24 Table 5,

Example 8 under HDWT Strain in water "214" should be 21.4

" {304050 (m'ss) 1 USCOMM-DC 60376-P69 '1 us. covznumsm mum-me omcz: m9 o-ass-m UNITED STATES PATENT OFF ICE CETTFTCATE OF CORRECTION Patent NO, 3,640,937 Dated 1 February a, 1972 lnventor(s) Oertel et a1 PAGE 4 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

COLUMN LINE ERROR 24 Table 5,

Example 21 under Residual Elongation "63" should be 36 Signed and sealed this 8th day of January 1974.

(SEAL) Attes't! EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer Acting Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 6O376-P69 u.s. GOVERNMENT PRINTING OFFICE: I989 0- 355-334 

